Developer Tools
Small utilities for coursework and projects: format and validate data, test patterns, decode tokens and try HTML, CSS and JavaScript in a live playground.
All developer tools (15)
Code Playground
Write, run, and preview HTML, CSS, and JavaScript instantly in your browser.
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JSON Formatter & Validator
Format, minify and validate JSON with clear error messages showing the line and column of the problem.
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JSON to CSV Converter
Convert JSON arrays to CSV for Excel or Google Sheets, with nested objects flattened into columns.
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Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text, with UTF-8 and URL-safe support.
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URL Encoder / Decoder
Percent-encode or decode URLs and query strings, and break a URL into its parts and parameters.
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JWT Decoder
Decode a JSON Web Token locally to inspect its header, payload and expiry. Decoding only, no signature verification.
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Regex Tester
Test JavaScript regular expressions with live match highlighting, capture groups and replacement preview.
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Markdown Editor & Live Preview
Write Markdown with a live, sanitised preview. Export as .md or a standalone .html file.
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SQL Formatter
Format messy SQL into readable, indented queries with consistent keyword casing, or minify it.
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UUID Generator
Generate random (v4) or time-ordered (v7) UUIDs in bulk with formatting options.
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Color Picker & Converter
Pick a colour and convert between HEX, RGB, HSL, HSV and CMYK, with contrast checks and shades.
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Timestamp Converter
Convert Unix timestamps to readable dates in any time zone, and dates back to Unix time.
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Code Line Counter
Count total, code, comment and blank lines in pasted code or multiple source files.
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Text Diff Checker
Compare two texts and see added and removed lines or words highlighted side by side.
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Lorem Ipsum Generator
Generate placeholder text as paragraphs, sentences or words for mockups and designs.
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